Space-age Skoda puts comet hunt in crisis

It is one of the more obscure objects in the heavens - a faint pinprick of light that occasionally flickers in the night sky as it travels on its remote orbit around the Sun.

But Comet Finlay could be destined for great things, for European engineers have earmarked it as a prime target for one of its most ambitious but ill-starred missions: the Rosetta project.

Scheduled for launch next month, the Rosetta spacecraft was intended to track another comet, Wirtanen, and land a robot probe on it to study the primordial constituents of the solar system, and to search for the building blocks of life. Comets are believed to be rich in such chemicals.

But last week the European Space Agency's plans were thrown into disarray when its Ariane 5 launcher exploded shortly after blast-off, destroying two communication satellites on board. Officials now face the prospect of putting the irreplaceable Rosetta on a rocket that has failed four times in 14 launches and earned itself the reputation as a space-age Skoda.

'Rosetta has to blast off by the end of January or it will miss its launch window,' said David Southwood, head of Esa's science division. 'However, if we don't get the most definite assurances from the rocket's operators, Arianespace, I will refuse to let the mission go ahead. This is the big one, and I do not want to go down as the man who blew it.'

Arianespace claims it can provide these assurances - a confidence shared by few other scientists. As a result, analysts at Esa's operations headquarters in Darmstadt, Germany, are now urgently rifling through star charts and computer programs in a bid to find other targets for the £250 million mission. Then its launch could be delayed for about a year, when Ariane 5's problems would hopefully be put right.

'Wirtanen's orbit lies within that of Jupiter, and makes it a relatively easy target - for a comet,' said Rosetta mission analyst José Rodríguez. 'Unfortunately, there aren't many other suitable Jupiter comets.'

Rosetta was supposed to take eight years to position itself in the shadow of Wirtanen and monitor gases and dust evaporating from its surface. Then it would drop a robot lander on to Wirtanen - a tricky business, given that gravity on the one-mile diameter comet would be too weak to hold down the craft. Instead it would have to harpoon itself to the surface.

It is a daring enterprise - though well worth the risks, scientists say. Most of the solar system's water is bound up in its comets. Indeed, water on Earth probably came from comets that bombarded our planet in its early history. In addition, comets are believed to be rich in organic molecules, the nutrients of life.

As planetary expert Professor Colin Pillinger says: 'Comets have played a critical role in the evolution of life on Earth. That is why scientists are so keen to land and study one. Unfortunately, we seem to have trouble finding the right one.'

So far, over the past 48 hours, Esa scientists have found a few options. These include Comet Finlay - named after a 19th-century astronomer W.H. Finlay - and a couple of comets discovered by Russians, Churyumov and Gerasimenko. However, changing tack in space is not easy. Wirtanen can be reached only by sending Rosetta on complex slingshot sweeps past Mars and Earth.

For its part, Arianespace says it still believes its Ariane 5 will be able to launch Rosetta in January.

'The version of Ariane 5 that failed was a new, experimental type. The one that will launch Rosetta is tried and tested,' said an Arianespace spokesman.

Few of the scientists involved in the mission take much comfort in such assurances, however.

'That claim is not strictly true,' said Dr Chris Carr, of Imperial College London. 'There will be new, untested components on the Ariane 5 that launches Rosetta.'

Or, as another Rosetta scientist said: 'It has taken 25 years to get Rosetta to the launch pad. That is half the working lifetime of all the scientists involved. You cannot risk launching such a mission on a rocket with such a wretched reputation as Ariane 5's. On the other hand, if we pick another target and go in a year's time, we may stretch the mission too far and blow it that way. It is a deeply unpleasant state of affairs.'

About this article

Space-age Skoda puts comet hunt in crisis

This article appeared on p11 of the Main section section of the Observer
on Saturday 14 December 2002.
It was published on
the Guardian website
at 04.56 EST on Sunday 15 December 2002.
It was last modified at 05.39 EDT on Wednesday 6 August 2014.
It was first published at 04.56 EST on Monday 16 December 2002.